package com.test;
 
import java.io.BufferedReader;  
import java.io.BufferedWriter;  
import java.io.FileInputStream;  
import java.io.FileNotFoundException;  
import java.io.FileOutputStream;  
import java.io.IOException;  
import java.io.InputStream;  
import java.io.InputStreamReader;  
import java.io.OutputStream;  
import java.security.Key;  
  
import javax.crypto.Cipher;  
import javax.crypto.CipherInputStream;  
import javax.crypto.spec.SecretKeySpec;  
  
import org.apache.http.entity.InputStreamEntity;  
  
/*** 
 * DES文件加密&解密  <br> 
 * 可以实现Android和window的文件互通  
 * @author spring.sky 
 * Email:vipa1888@163.com 
 * QQ:840950105 
 * 
 */  
public class EncryptAndDecryption {  
    /**加密解密的key*/  
    private Key mKey;  
    /**解密的密码*/  
    private Cipher mDecryptCipher;  
    /**加密的密码*/  
    private Cipher mEncryptCipher;  
    public EncryptAndDecryption(String key) throws Exception  
    {  
        initKey(key);  
        initCipher();  
    }  
      
    /** 
     * 创建一个加密解密的key 
     * @param keyRule  
     */  
    public void initKey(String keyRule) {  
        byte[] keyByte = keyRule.getBytes();  
        // 创建一个空的八位数组,默认情况下为0   
        byte[] byteTemp = new byte[8];  
        // 将用户指定的规则转换成八位数组   
        for (int i = 0; i < byteTemp.length && i < keyByte.length; i++) {  
            byteTemp[i] = keyByte[i];  
        }  
        mKey = new SecretKeySpec(byteTemp, "DES");  
    }  
      
    /*** 
     * 初始化加载密码 
     * @throws Exception 
     */  
    private void initCipher() throws Exception  
    {  
        mEncryptCipher = Cipher.getInstance("DES");  
        mEncryptCipher.init(Cipher.ENCRYPT_MODE, mKey);  
          
        mDecryptCipher = Cipher.getInstance("DES");  
        mDecryptCipher.init(Cipher.DECRYPT_MODE, mKey);  
    }  
      
    /** 
     * 加密文件 
     * @param in 
     * @param savePath 加密后保存的位置 
     */  
    public void doEncryptFile(InputStream in,String savePath)  
    {  
        if(in==null)  
        {  
            System.out.println("inputstream is null");  
            return;  
        }  
        try {  
            CipherInputStream cin = new CipherInputStream(in, mEncryptCipher);  
            OutputStream os = new FileOutputStream(savePath);  
            byte[] bytes = new byte[1024];  
            int len = -1;  
            while((len=cin.read(bytes))>0)  
            {  
                os.write(bytes, 0, len);  
                os.flush();  
            }  
            os.close();  
            cin.close();  
            in.close();  
            System.out.println("加密成功");  
        } catch (Exception e) {  
            System.out.println("加密失败");  
            e.printStackTrace();  
        }  
    }  
      
    /** 
     * 加密文件 
     * @param filePath 需要加密的文件路径 
     * @param savePath 加密后保存的位置 
     * @throws FileNotFoundException  
     */  
    public void doEncryptFile(String filePath,String savePath) throws FileNotFoundException  
    {  
        doEncryptFile(new FileInputStream(filePath), savePath);  
    }  
      
      
    /** 
     * 解密文件 
     * @param in 
     */  
    public void doDecryptFile(InputStream in)  
    {  
        if(in==null)  
        {  
            System.out.println("inputstream is null");  
            return;  
        }  
        try {  
            CipherInputStream cin = new CipherInputStream(in, mDecryptCipher);  
            BufferedReader reader = new BufferedReader(new InputStreamReader(cin)) ;  
            String line = null;  
            while((line=reader.readLine())!=null)  
            {  
                System.out.println(line);  
            }  
            reader.close();  
            cin.close();  
            in.close();  
            System.out.println("解密成功");  
        } catch (Exception e) {  
            System.out.println("解密失败");  
            e.printStackTrace();  
        }  
    }  
    /** 
     * 解密文件 
     * @param filePath  文件路径 
     * @throws Exception 
     */  
    public void doDecryptFile(String filePath) throws Exception  
    {  
        doDecryptFile(new FileInputStream(filePath));  
    }  
      
      
    public static void main(String[] args)throws Exception {  
    	EncryptAndDecryption fileDES = new EncryptAndDecryption("spring.sky");  
        fileDES.doEncryptFile("d:/a.txt", "d:/b");  //加密   
        fileDES.doDecryptFile("d:/b"); //解密   
    }  
      
}  
